BACKGROUND/AIMS: The understanding of histopathological prognostic fac
tors is critical to improving surgical outcome. This study investigate
d the microscopic features of cancer of the extrahepatic bile duct in
order to clarify the prognostic determinants affecting surgical outcom
e. METHODOLOGY: In 90 cancers of the extrahepatic bile duct, the corre
lation between several microscopic parameters and survival was investi
gated. Lymphatic, venous, and perineural invasion, and the surgical ma
rgin (tumor-free or tumor-positive) were examined with serial step-wis
e sectioned specimens. RESULTS: Seven pT1-tumors showed no venous or p
erineural invasion and no lymph node involvement and were associated w
ith prolonged survival (5 year survival, 86%) compared with pT2,3 tumo
rs (23%). In pT2,3 tumors, lymphatic, venous, and perineural invasion
was found in 80%, 47%, and 88%, respectively, with no significant diff
erences in occurrence of these parameters according to the origin of t
he primary tumor. As for survival with pT2,3 tumors, lymph node involv
ement (58%) and status of the surgical margin were significant paramet
ers (p=.0330 and p=.0309, respectively). In addition, these latter par
ameters differed significantly according to the origin of the primary
tumor. CONCLUSION: In cancer of the extrahepatic bile duct, lymph node
involvement and status of the surgical margin were the most important
microscopic parameters affecting prognosis.